Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

<image>

In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
inline void pisz(int n) { printf("%d\n", n); }
template <typename T, typename TT>
ostream& operator<<(ostream& s, pair<T, TT> t) {
  return s << "(" << t.first << "," << t.second << ")";
}
template <typename T>
ostream& operator<<(ostream& s, vector<T> t) {
  for (int(i) = 0; (i) < (((int)((t).size()))); ++(i)) s << t[i] << " ";
  return s;
}
const int N = 667;
int s[N][N];
int main() {
  int(n), (m);
  scanf("%d %d", &(n), &(m));
  ;
  for (int(i) = 1; (i) <= (n); ++(i))
    for (int(j) = 1; (j) <= (m); ++(j)) scanf("%d", &s[i][j]);
  vector<pair<string, int>> res;
  if (n > m) {
    for (int(j) = 1; (j) <= (m); ++(j)) {
      int mi = s[1][j];
      for (int(i) = 1; (i) <= (n); ++(i)) (mi) = min((mi), (s[i][j]));
      ;
      for (int(u) = 0; (u) < (mi); ++(u)) res.push_back(make_pair("col", j));
      for (int(i) = 1; (i) <= (n); ++(i)) s[i][j] -= mi;
    }
    for (int(i) = 1; (i) <= (n); ++(i)) {
      for (int(j) = 1; (j) <= (m); ++(j))
        if (s[i][1] != s[i][j]) {
          pisz(-1);
          return 0;
        }
      for (int(u) = 0; (u) < (s[i][1]); ++(u))
        res.push_back(make_pair("row", i));
    }
  } else {
    for (int(i) = 1; (i) <= (n); ++(i)) {
      int mi = s[i][1];
      for (int(j) = 1; (j) <= (m); ++(j)) (mi) = min((mi), (s[i][j]));
      ;
      for (int(u) = 0; (u) < (mi); ++(u)) res.push_back(make_pair("row", i));
      for (int(j) = 1; (j) <= (m); ++(j)) s[i][j] -= mi;
    }
    for (int(j) = 1; (j) <= (m); ++(j)) {
      for (int(i) = 1; (i) <= (n); ++(i))
        if (s[1][j] != s[i][j]) {
          pisz(-1);
          return 0;
        }
      for (int(u) = 0; (u) < (s[1][j]); ++(u))
        res.push_back(make_pair("col", j));
    }
  }
  pisz(((int)((res).size())));
  for (auto it : res) cout << it.first << ' ' << it.second << '\n';
}